This particular debate began earlier this week, when AT&T sent the FCC a letter (PDF) arguing that telecommunications providers need the ability to set different prices for different forms of Internet service. Paid prioritization, AT&T said, was a form of network management that was "fully contemplated by the IETF" more than a decade ago.

At 24 years old, the IETF is a highly respected organization of engineers and computer scientists that intentionally shies away from Washington politicking. That's partly because the group is international--half of its meetings are held outside North America--but also because IETF participants tend to admit that they have relatively little expertise in non-technical areas touching on law and economics.

AT&T did not immediately respond to a request for comment on Thursday. AT&T Vice President Hank Hultquist said in a blog post earlier in the day that he was inviting critics to a "public forum," and pointed to a letter from the New America Foundation that he said lent support to AT&T's views.

"We didn't foresee AT&T throwing our name into this discussion," the IETF's Housley said. He added: "This characterization of the IETF standard and the use of the term 'paid prioritization' by AT&T is misleading."

Everyone agrees that, in the late 1990s, the IETF revised its networking standards to allow network operators to assign up to 64 different traffic "classes," meaning priority levels. That concept of "differentiated services" is referred to today as DiffServ, which allows high-priority communications like videoconferencing to be labeled with a higher priority than bulk file-transfer protocols that aren't as sensitive to brief slowdowns.

A July 1999 IETF specification (RFC 2638) discusses paid prioritization by saying: "It is expected that premium traffic would be allocated a small percentage of the total network capacity, but that it would be priced much higher." Another specification (RFC 2475) published half a year earlier says that setting different priorities for packets will "accommodate heterogeneous application requirements and user expectations" and "permit differentiated pricing of Internet service." (An RFC is a policy document, often accepted as standards, published by the IETF.)

The disagreement arises from what happens if Video Site No. 1 and Video Site No. 2 both mark their streams as high priority. "If two sources of video are marking their stuff the same, then that's where the ugliness of this debate begins," Housley says. "The RFC doesn't talk about that...If they put the same tags, they'd expect the same service from the same provider."

Which is, by the way, more or less what liberal advocacy groups like Free Press have told the FCC. "DiffServ was not designed to be a tool to allow the network provider to drive application-level discrimination," Free Press Research Director Derek Turner said earlier this week.

Ever since a federal appeals court torpedoed the FCC's attempt to punish Comcast, pro-regulation groups have been lobbying agency Chairman Julius Genachowski for a new set of regulations, while a majority of members of the U.S. Congress has opposed the idea. Google and Verizon responded by announcing their own proposal, which includes a "presumption" that paid prioritization on wired networks is illegal.

On the broader question of Net neutrality, though, including what any laws or regulations should say, the IETF has not taken a formal position. The group discussed the topic at a meeting in Stockholm in July 2009 but did not reach a consensus leading to a public position statement.

Update Friday 12:30 a.m. PDT: I heard back from AT&T spokesman Michael Balmoris, who said: "Our letter highlighted recent Free Press filings at the FCC, which insisted that compensation arrangements were inconceivable under the IETF documentation for Differentiated Services (DiffServ). We simply quoted from the IETF documents, which state otherwise."

And there seems to be some disagreement about whether Russ Housley was speaking for the entire IETF. George Ou, policy director at the Digital Society think tank, sent me e-mail analyzing the RFCs and saying: "In the context of Housley essentially calling AT&T a liar, his comments are outrageously deceptive."